Just a decade and a half as it turns out! (though things definitely felt dizzyingly fast back then - think Google was launched just 5 years after HTML)
ActiveX XMLHTTP might have been released in 99, but it didn’t see any sort of real wider usage until 2004, 2005. I’d suggest its usage was really kickstarted when jQuery 1.0 launched in 2006 and standardised the interface to a simple API.
Gmail was the first time I saw a website which could refresh the information without refreshing the page. I was a teen back then but I realized it was something momentous.
OK, but I think it was Google Maps that made the experience of not needing to refresh the page popular (while being shown more information from the server).
For a long time, you needed an invite to sign up for Gmail, so you couldn't easily share the cool experience of AJAX with others like you would with a Google Maps link.
> it was Google Maps that made the experience of not needing to refresh the page popular
IMO that's a reasonable impression of the times unless I'm forgetting something (and the additional observation about sharing--"virality" as it was called, before you know--was insightful).
At the time the previous "state of the art" was something like MapQuest which IIRC had a UI that essentially displayed a single tile and then required you to click on one of four directional arrow images to move the visible portion of the map, triggering a page load in the process (maybe a frame load?).
Yahoo! also "participated" in the mapping space at the time.
In the event anyone's interested in further ancient history around the topic, this page is actually (to my surprise) still online (with many broken links presumably): https://libgmail.sourceforge.net/googlemaps.html
(It's what we did for fun in the Times Before Social Media. :D )
It's important to understand that we had "AJAX" before we had AJAX, if you see what I mean.
I was part of a team that deployed an e-commerce site that made international news in 1998, that used AJAX-type techniques in a way that worked in IE3 on Windows 3.11. (Though this was not part of the media fuss at the time; that was more about the fact of being able to pay for things online, still)
The arrival of XMLHTTPRequest made it possible to do everything with core technology, but it was already possible to do asynchronous work in JS by making use of a hidden frame.
You could direct that frame to load a document, the result of which would be only a <script> tag containing a JS variable definition, and the last thing that document would do is call a function in the parent frame to hand over its data. Bingo: asynchronous JS (that looked essentially exactly like JSON).
Since there were also various hacky ways in each browser to force a browser to reload page from cache (that we exhaustively tested), and you could do document.write(), it was possible to trigger a page to regenerate from asynchronous dynamic data in a data store in the parent frame, using a purely static page to contain it.
In this way we really radically cut down the server footprint needed for a national rollout, because our site was almost entirely static, and we were also able to secure with HTTPS all of the functions that actually exchanged customer data, without enduring the then 15-25% CPU overhead of SSL at either end (this is before Intel CPUs routinely had the instruction sets that sped up encryption). We also ended up with a site that was fast over a 33.6 modem.
This was a pretty novel idea at the time -- we were the only people doing it that we knew of -- but over the years I have found we were not the only team in the world effectively inventing this technique in parallel, a year or 18 months before XMLHTTPRequest was added to browsers.
(IE3 on Windows 3.11 was a good experience, by the way. Better behaved and more consistent than Netscape)
At around the same time we were also exploring things like using Java applets to maintain encrypted channels and taking advantage of the very limited ways one had to get data in and out of an applet. For example you couldn't push out from an applet to the page easily, but you could set up something that polled the applet and called the functions it wanted.
I don't like to get all "get off my lawn" but it feels like we actually earned our keep back then, getting technologies to do stuff that no standards working group anywhere was really considering and for which precious little documentation actually existed. There's a generation of us who held our copies of "Webmaster In A Nutshell" and "Java In A Nutshell" very close.
